Windows 10: Microsoft Defender SmartScreen - Certificate Encoding Error

I am a developer who has published a new installer for my application. Windows Defender SmartScreen keeps popping up the following screen, which contains an obvious encoding error for a string that is clearly read from the application's signature block:Basically, the Polish 'Ł' character is displayed as U+FFFD, the Unicode "Replacement Character". Note that this screen is incorrect in this way only if, in the "Administrative Language Settings" / "Language for non-Unicode programs" settings panel, the "Current System Locale" is set to "Polish" yes, Polish. If that setting is "English", the

:)

 

Microsoft Defender Smartscreen

Hi COLINGILBERT1,

Sorry to hear you're experiencing this issue. I'm an Independent Advisor and consumer of Microsoft products just like you. Let me help you with your concern.

Microsoft Defender SmartScreen checks downloaded files against a list of reported malicious software sites and known unsafe programs and against list of files that are well known and downloaded by many Windows users. If the file you downloaded is on the malicious
list or is not commonly downloaded it will show a warning, advising caution. If you believe that the file is not malicious and you trust the source then you can ignore the warning by clicking "Run anyway".

Refer to the below link for the benefits of Microsoft Defender SmartScreen.

https://docs.microsoft.com/en-us/windows/securi...

 

Defender/SmartScreen warning.

Though this doesn't explain why an application's specific reputation might have changed, the addition of granular controls for these settings in the recently released Windows 10 Creators Update may have something to do with it.

Smartscreen in Creators Update

This newer implementation of SmartScreen within Windows 10 has also been renamed to

Windows Defender SmartScreen rather than the old Windows SmartSreen and SmartScreen Filter name within the browser.

Again, none of this specifically explains a change in reputation, but it's possible that all of these changes might have affected the reputation for some applications or certificates.

Since you didn't specify what type of certificate you are using, since this affects the ability to add or gain reputation status more quickly. The

Windows Defender SmartScreen® Filter Frequently Asked Questions page covers this as follows.

There are industry best practices for application developers that will affect your download's reputation and help ensure reputation is established and maintained. If your program is not digitally signed, reputation cannot automatically be shared
across different versions and builds.

To help establish your application's reputation, consider doing the following:

• Digitally sign your programs with an Authenticode signature
  
  Reputation is generated and assigned to digital certificates as well as specific files. Digital certificates allow data to be aggregated and assigned to a single certificate rather than many individual programs. Only Authenticode Certificates issued by a Certificate
  Authority (CA) that is a member of the Windows Root Certificate Program can establish reputation.
• Apply for a Windows Logo
  
  To learn more visit the
  Windows Logo Program page on MSDN.

Rob

 

Windows Defender SmartScreen won't let me download ANYTHING.

Hello,

Thank you for writing to Microsoft Community Forums.

Please provide some additional information, so that we can assist you better.

1. Which browser you are using to download the application?
   
2. What is the complete error message appears on your computer screen when you click on download?
   
   

We can try and perform few steps and see if it helps.

Step 1: You can refer the Microsoft article related

Windows Defender SmartScreen under the section
how can I download files reported as unsafe by Windows Defender SmartScreen in Internet Explorer 10 or Microsoft Edge.

Step 2: Try to disable SmartScreen.

1. Press Windows + S on your keyboard.
   
2. Click on Internet Options.
   
3. When the Internet Properties window opens, go to the
   Security tab and click Custom level.
   
4. Locate the Miscellaneous section. Now, locate Use
   SmartScreen Filter option and set it to disable. Click OK to save changes.
   
5. You can disable SmartScreen by going to the
   advanced tab and unchecking the Enable SmartScreen Filter option. After doing that, click
   Apply and OK to save changes.
   
6. Restart your computer to effect the settings.
   

Hope it helps.

Let us know if you got the help you needed by clicking ‘Yes or No’.

Harish

Microsoft Community – Moderator